Better default flags (#791)

Before this commit, only the one letter flags interpreted
as tree options were supported.

Now
- the -c (or --cmd) argument is also supported
- long form arguments are supported

Examples:

    default_flags: "-s -c thing -gh"
    default_flags: "gh" // old syntax
    default_flags: --show-git-info --only-folders

1 files changed, 5 insertions, 4 deletions

diff --git a/website/docs/conf_file.md b/website/docs/conf_file.md
index 96efbe8..f098af9 100644
--- a/website/docs/conf_file.md
+++ b/website/docs/conf_file.md
@@ -78,7 +78,8 @@ Starting from version 1.14, the default configuration is released in several fil
 
 # Default flags
 
-Broot accepts a few flags at launch (the complete list is available with `broot --help`.
+Broot accepts a few flags at launch (the complete list is available with `broot --help`).
+The `default_flags` entry lets you specify them in configuration, with the same syntax.
 
 For example, if you want to see hidden files (the ones whose name starts with a dot) and the status of files related to git, you launch broot with
 
@@ -87,13 +88,13 @@ For example, if you want to see hidden files (the ones whose name starts with a
 If you almost always want those flags, you may define them as default in the configuration file file, with the `default_flags` setting.
 
 ```Hjson
-default_flags: gh
+default_flags: -gh
 ```
 ```TOML
-default_flags = "gh"
+default_flags = "-gh"
 ```
 
-Those flags can still be overridden at launch with the negating ones. For example if you don't want to see hidden files at a specific launch, do
+Those flags can still be overridden at launch with the negating ones. For example, with the above `default_flags`, if you don't want to see hidden files on a specific launch, do
 
     br -H